1. Field of the Invention
The present invention generally relates to blended fuels, where a low carbon fuel, ideally derived from a production process that uses a renewable, biomass feedstock, is blended with a traditional, petroleum derived fuel. Such blended fuels result in an overall improved well-to-wheels greenhouse gas content, as well as improved performance characteristics of the fuels, compared to the petroleum derived fuels.
2. Description of Related Art
Global demand for energy continues to rise at a significant rate, particularly among emerging industrialized nations. Biomass and other alternative carbon resources are becoming more attractive as renewable energy sources due to increasing energy costs as well as for environmental reasons.
Various types of fuels produce different amounts of greenhouse gases during their entire lifecycle (e.g., during fuel production, transportation, and consumption). Thus, these fuels have different impacts on the environment. One way to compare the greenhouse gas effect of each fuel is by calculating and comparing well-to-wheels greenhouse gas content to the well-to-wheels greenhouse gas content of a petroleum fuel (or “baseline” fuel).
A well-to-wheels greenhouse gas content (“WWGGC”) refers to a calculation that is done using a greenhouse gas model, such as Argonne National Laboratories GREET model (currently in version 1.8d.1 which can be downloaded at http://greet.es.anl.gov/) or another similar greenhouse gas model. The model allows for the calculation of the amount of greenhouse gases that are produced throughout the entire lifecycle of the product (from “well to wheels”). The model takes into account, among other things, the production method, the feedstock used in the production, the type of fuel produced, transportation of the fuel to market, and the emissions produced from combustion of the fuel when it is used.
Petroleum derived fuels, such as gasoline and diesel fuel that are refined from oil using a traditional production method, produce a large amount of greenhouse gases. For example, diesel production from oil results in a well to well to wheels greenhouse gas production content of 383 gCO2e/mi (all WWGGC scores referenced in this document are calculated using version 1.8d.1 of the GREET model which can be downloaded at http://greet.es.anl.gov/ and which provides archives of all older versions of the software). The units' gCO2e/mi means the grams of carbon dioxide equivalent greenhouse gases that result from travelling one mile in a vehicle using the fuel. Other fuels, such as first generation biofuels (e.g., ethanol derived from corn), also score close to or greater than petroleum derived fuels in terms of WWGGC calculated according to the GREET model, thus providing no significant WWGGC benefit over petroleum fuels. For example, E85 (meaning 85% ethanol and 15% gasoline, where the ethanol is derived from corn) receives a WWGGC of 358 gCO2e/mi.
Some of synthetic fuels that are produced from a biomass feedstock, using thermochemical or biochemical conversion processes, can achieve lifecycle greenhouse gas scores that are greater than 50% lower than traditional, petroleum derived fuels (e.g., a WWGGC score of lower than 191 using the GREET model). When comparisons are made, the same vehicle is used in the GREET model for comparison. While biofuels produced from existing known methods today may achieve an improved WWGGC compared to petroleum fuels, when blended with petroleum fuels, the engine performance characteristics of the blended fuels are sometimes reduced compared to the neat petroleum fuels. For example, blending such synthetic fuels with the petroleum fuel can reduce the engine performance characteristics of the petroleum fuel, such as a cetane number, lubricity, and increase emissions.
There is a need for an alternative fuel derived from a biomass feedstock, which when blended with a petroleum fuel, not only significantly improves WWGGC, but also improves the engine performance characteristics of the blended fuels. The present invention meets these needs as well as others and provides a substantial improvement over the prior art.